scholarly journals Behavioral effects of the neurotoxin ß-N-methylamino-L-alanine on the mangrove rivulus (Kryptolebias marmoratus) larvae

Author(s):  
Alessandra Carion ◽  
Julie Hétru ◽  
Angèle Markey ◽  
Victoria Suarez-Ulloa ◽  
Silvestre Frédéric

Mangrove rivulus, Kryptolebias marmoratus, is a hermaphrodite fish capable of self-fertilization. This particularity allows to naturally produce highly homozygous and isogenic individuals. Despite the low genetic diversity, rivulus can live in extremely variable environments and adjust its phenotype accordingly. This species represents a unique opportunity to clearly distinguish the genetic and non-genetic factors implicated in adaptation and evolution, such as epigenetic mechanisms. It is thus a great model in aquatic ecotoxicology to investigate the effects of xenobiotics on the epigenome, and their potential long-term impacts. In the present study, we used the mangrove rivulus to investigate the effects of the neurotoxin ß-N-methylamino-L-alanine (BMAA) on larvae behaviors after 7 days exposure to two sub-lethal concentrations. Results show that BMAA can affect the maximal speed and prey capture (trials and failures), suggesting potential impacts on the organism’s fitness.

2021 ◽  
Author(s):  
Jennifer D Gresham ◽  
Ryan L Earley

AbstractMixed mating, a reproduction strategy utilized by many plants and invertebrates, optimizes the cost to benefit ratio of a labile mating system. One type of mixed mating includes outcrossing with conspecifics and self-fertilizing one’s own eggs. The mangrove rivulus fish (Kryptolebias marmoratus)is one of two vertebrates known to employ both self-fertilization (selfing) and outcrossing. Variation in rates of outcrossing and selfing within and among populations produces individuals with diverse levels of heterozygosity. I designed an experiment to explore the consequences of variable heterozygosity across four ecologically relevant conditions of salinity and water availability (10‰, 25‰, and 40‰ salinity, and twice daily tide changes). I report a significant increase in mortality in the high salinity (40‰) treatment. I also report significant effects on fecundity measures with increasing heterozygosity. The odds of laying eggs decreased with increasing heterozygosity across all treatments, and the number of eggs laid decreased with increasing heterozygosity in the 10‰ and 25‰ treatments. Increasing heterozygosity also was associated with a reduction liver mass and body condition in all treatments. My results highlight the fitness challenges that accompany living in mangrove forests ecosystem and provide the first evidence for outbreeding depression on reproductive and condition-related traits.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
G. C. Conroy ◽  
R. W. Lamont ◽  
L. Bridges ◽  
D. Stephens ◽  
A. Wardell-Johnson ◽  
...  

AbstractThe dingo population on world heritage-listed K’gari-Fraser Island (K’gari) is amongst the most well-known in Australia. However, an absence of population genetic data limits capacity for informed conservation management. We used 9 microsatellite loci to compare the levels of genetic diversity and genetic structure of 175 K’gari dingo tissue samples with 264 samples from adjacent mainland regions. Our results demonstrated that the K'gari population has significantly lower genetic diversity than mainland dingoes (AR, HE, PAR; p < 0.05) with a fourfold reduction in effective population size (Ne = 25.7 vs 103.8). There is also strong evidence of genetic differentiation between the island and mainland populations. These results are in accordance with genetic theory for small, isolated, island populations, and most likely the result of low initial diversity and founder effects such as bottlenecks leading to decreased diversity and drift. As the first study to incorporate a large sample set of K’gari dingoes, this provides invaluable baseline data for future research, which should incorporate genetic and demographic monitoring to ensure long-term persistence. Given that human-associated activities will continue to result in dingo mortality, it is critical that genetic factors are considered in conservation management decisions to avoid deleterious consequences for this iconic dingo population.


Impact ◽  
2020 ◽  
Vol 2020 (3) ◽  
pp. 63-65
Author(s):  
Tomomi Higashi

Talk to any allergy sufferer and they will tell you how awful it can be. Runny noses, itchy eyes, coughing and difficulties breathing. For many these symptoms rise only to the level of annoyance and can be avoided by steering clear of the source of their allergy. What many people don't realise though is that allergies can become a far more serious issue for a large segment of the population. Shortness of breath and difficulty breathing due to allergies bring many people to emergency rooms and these are just the acute symptoms. Along with the potential for an allergic attack during a windy or dusty day, researchers and medical professionals are beginning to recognise that there are chronic, long term effects associated with allergies. In order to mitigate both the acute and chronic effects of allergies a better understanding of how genetic factors combine with environmental conditions to produce the ranges of symptoms and effects of allergy suffers is needed. Professor Tomomi Higashi, from the Department of Hygiene at Kanazawa University in Japan, is an expert in this field and is currently working to improve treatment and prevention of allergic disease.


Author(s):  
Olli-Pekka Nuuttila ◽  
Ari Nummela ◽  
Keijo Häkkinen ◽  
Santtu Seipäjärvi ◽  
Heikki Kyröläinen

The purpose of the study was to examine the effects of progressively increased training intensity or volume on the nocturnal heart rate (HR) and heart rate variability (HRV), countermovement jump, perceived recovery, and heart rate-running speed index (HR-RS index). Another aim was to analyze how observed patterns during the training period in these monitoring variables were associated with the changes in endurance performance. Thirty recreationally trained participants performed a 10-week control period of regular training and a 10-week training period of either increased training intensity (INT, n = 13) or volume (VOL, n = 17). Changes in endurance performance were assessed by an incremental treadmill test. Both groups improved their maximal speed on the treadmill (INT 3.4 ± 3.2%, p < 0.001; VOL 2.1 ± 1.8%, p = 0.006). In the monitoring variables, only between-group difference (p = 0.013) was found in nocturnal HR, which decreased in INT (p = 0.016). In addition, perceived recovery decreased in VOL (p = 0.021) and tended to decrease in INT (p = 0.056). When all participants were divided into low-responders and responders in maximal running performance, the increase in the HR-RS index at the end of the training period was greater in responders (p = 0.005). In conclusion, current training periods of increased intensity or volume improved endurance performance to a similar extent. Countermovement jump and HRV remained unaffected, despite a slight decrease in perceived recovery. Long-term monitoring of the HR-RS index may help to predict positive adaptations, while interpretation of other recovery-related markers may need a more individualized approach.


2021 ◽  
pp. 1-5
Author(s):  
Asma Saghir Khan

Childhood, overweight and obesity are increasingly significant problems, and ones that are likely to endure and to have long term adverse influences on the health of individuals and populations unless action is taken to reverse the trend. A number of factors have been suggested as contributing to the development of childhood obesity. These include genetic factors, decreasing levels of physical activity, increased time spent in sedentary behavior and changes in diet. In addition, lifestyle factors, including family influences, changes in society and media advertising, have been associated with the increasing incidence of obesity and overweight in childhood. To address the problem, health care professionals should incorporate appropriate screening in their child practice. Comprehensive assessment of children who are, or who are at risk of becoming, obese is also necessary


2016 ◽  
Vol 8 (4) ◽  
pp. 100
Author(s):  
Azza A. M. H. Swar Aldahab ◽  
Abdallah. O. Elkhawad

Anticoagulation with warfarin is characterized by a wide inter-individual variations in dose requirements and INR (International Normalised Ratio) stability, as there are evidences that warfarin response variability is associated with CYP2C9 (cytochrome P450, family 2, subfamily C, polypeptide 9) and VKORC1 (Vitamin K epoxide reductase complex1) genetic polymorphisms. Carriers of CYP2C9*2 and VKORC11639G&gt;A variant alleles are at greater risk of unstable anticoagulation therapy. Objectives: This retrospective case control study was directed to analyze the impact of genetic and non-genetic factors on warfarin therapy in Sudanese out-patients who were on long term warfarin therapy. Method: 118 Sudanese outpatients receiving warfarin treatment for at least six months, were interviewed for their non-genetic factors that included age, sex, indication for warfarin therapy, compliance, Vitamin K rich foods intake and concomitant drug therapy, in addition to their blood samples which were taken for DNA extraction and genotyping of CYP2C9*2 and VKORC11639G&gt;A gene polymorphisms to study the genetic factors. INR stability % index was calculated, accordingly patients were classified into 2 groups, stable and unstable groups. Results: The frequencies of VKORC11639G&gt;A alleles in Sudanese out-patients who were on long term warfarin therapy were 70.3% and 29.7% for the VKORC1/G and VKORC1/A alleles respectively. The frequencies of CYP2C9*2 alleles in Sudanese out-patients were 92.4% and 7.6% for CYP2C9*1 and CYP2C9*2 alleles respectively. Variables associated with low INR stability were VKCOR1/AA genotype (p-value = 0.028) and sex (p = 0.017). Variables that showed no association with INR stability were age (p-value = 0.259), compliance (p-value = 0.058). Vitamin K rich foods intake (p- value = 0.743), and mean stable warfarin dose (p-value = 0.439). Conclusion: Polymorphism in warfarin drug target gene VKORC1-11639G&gt;A and sex are important elements of INR stability in Sudanese out- patients on long term warfarin therapy.


Genes ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1855
Author(s):  
Justyna Chojdak-Łukasiewicz ◽  
Edyta Dziadkowiak ◽  
Sławomir Budrewicz

Strokes are the main cause of death and long-term disability worldwide. A stroke is a heterogeneous multi-factorial condition, caused by a combination of environmental and genetic factors. Monogenic disorders account for about 1% to 5% of all stroke cases. The most common single-gene diseases connected with strokes are cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) Fabry disease, mitochondrial myopathy, encephalopathy, lactacidosis, and stroke (MELAS) and a lot of single-gene diseases associated particularly with cerebral small-vessel disease, such as COL4A1 syndrome, cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), and Hereditary endotheliopathy with retinopathy, nephropathy, and stroke (HERNS). In this article the clinical phenotype for the most important single-gene disorders associated with strokes are presented. The monogenic causes of a stroke are rare, but early diagnosis is important in order to provide appropriate therapy when available.


2004 ◽  
pp. 181-190
Author(s):  
Mirjana Sijacic-Nikolic ◽  
Aleksandar Tucovic ◽  
Dragica Vilotic

The main data on the occurrence of semi-dwarfs in the subspontaneous progeny of American red oak were researched. The grafting of scions from semi-dwarf trees on the stock of related species shortens the juvenile stage, i.e. accelerates the flowering, induces the self-fertilization and potential crossing of related species. The specific undertaking requires to: (1) define the desired type of the dwarf cultivar, (2) develop the model, and (3) plan the genetic nature of the conceived cultivar. The development of cultivars relies on the conceived and long-term activity.


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